There is a constant demand for ever-smaller camera modules. This demand is in large part driven by a desire to shrink the size of systems to which cameras are incorporated, such as cellular phones, but also by cost considerations since the material cost decreases with camera size. There are numerous obstacles for shrinking the size of camera modules. Some of these obstacles are associated with the image sensor itself, whereas others are associated with packaging of the camera. A typical prior-art image sensor package 100 is shown in FIG. 1. Image sensor package 100 includes (a) a substrate 120, (b) an image sensor 110 bonded to a recessed surface 122 of substrate 120, and (c) a cover glass 130 bonded to a top surface 124 of substrate 120. Cover glass 130 protects image sensor 110 against moisture, dirt, and other potential damage. Cover glass 130 is sealed to top surface 124 at a planar sealing interface 140. This sealing interface 140 must have a certain width 144 to both reliably bond cover glass 130 to substrate 120 and prevent, or at least minimize, penetration of moisture through the glue used to seal cover glass 130 to substrate 120. The transverse extent 150 of prior-art image sensor package 130 is the sum of (i) the size 152 of the region required to accommodate image sensor 110 and electrical connections thereto and (ii) two times width 144.
In operation, prior-art image sensor package 100 is coupled with an imaging objective 170 (such as one or more lenses) to form a camera module 190. Imaging objective 170 images a scene 180 through cover-glass 130 onto image sensor 110. Image sensor 110 detects light transmitted by cover glass 130 and incident on the light-receiving surface 112 of image sensor 110.